CULTIVATION OF SILK.

Cultivation of silk:,-

image of , the man spool silk.

image of the cocoon.

Silk moth lay eggs on specially prepared paper. The eggs are hetch and the cater pillars (silkworm) are fed fresh mulbery leaves. After about 35 days and 4 moltings  the caterpillars are 19,000  times heavier than when hatched and ready to begn spinning a cocoon. A straw frame is placed over the tray of catterpillars and each catterpillars begin spinning a cocoon by moving its head in a pattern. Two glands produce liquid silk and force it through openings in the head called spinnerate. Liquid silk is coated in sericin a water soluble protective gum, and solidifies on contact with the air within 2-3 days , the caterpillar spins about one mile (1.6 km,) of filament and completely encased in cocoon. The silk farmer then heat the cocoon to kill them, leaving some to metamophose into moths to breed the next generation of catterpillars Harvested cocoons are then soaked in boiling water to soften the seicin holding the silk fibers together in a cocoon shape . The fibers are then unwound to produce a continuous threads . Since a single threads is too fine  and fragile for  commecial use, any where from three to ten standard are spun together to form a single thread of silk.

SERICULTURE:-

Sericulture or silk farming is the cultivation of silk worms to produce silk. Although there are several commercial species of silk worms, Bombyx mori (the caterpillar of the domestic, silk moth) is the most wide used and intensively studied silk worm. Silk was believe to have first been produced in China as early as the Neolithic period sericulture has become and important cottage industry in countries such as a Brazil, China , France, India , Itly, Japan, korea , and Russia, Today china and India are the two main producers, with more than 60% of the worlds annual production. 

image of silk worm and cocoon.

Production of sericulture silk,:-

The silk worms are fed with mulbery leaves , and after the fourth moult , they climb a twig placed near them and spin their silken cocoons. The silk is continuous filament comprising fibroin protein, secreted from two salivary glands in the head of each each worm and sbhum called sericin , which cements the filaments. The sericin is removed by placing the cocoon in hot water, which free silk filaments and readies them degumming process . The immersion in that water also kills the silk moth pupa.

Single filament are combine to form threads in a process called "throwing" which is drawn under tension through several guide and wound onto reels. The process of throwing produces various yarn on the amount and direction of twisting. The threads may be plied  to form yarn ,(short staple lengthd are spun: see silk noil). After drying the raw silk is packed according to quality.

 Ref:-https://en.m.wikipedia..org